The Asiatic division of the Tragelaphine group, which, in the existing stage of the Earth’s fauna, is represented only by the present species, is nearly as different in its structure as it is in its geographical range from its African brethren, being at once distinguishable by its short hind limbs, untwisted horns, bovine nose, and hypsodont molars, not to mention its very different style of colour. The Asiatic form might, in fact, be more naturally arranged as constituting a Subfamily of itself, but we are content to follow recent authorities who have associated this animal with the more typical Tragelaphs of Africa. The “Nilgai” (said by some authorities to be more correctly written “Nilgau,” from _nil_ or _lil_, blue, and _gau_, cow) was first introduced into scientific literature by Pallas in his memoir on the genus _Antilope_ published in 1766. Pallas’s “_Antilope tragocamelus_,” as he called this species, was based partly upon Ray, who quoted from Gesner, and partly on the description of Dr. James Parsons, F.R.S., who, in the forty-third volume of the ‘Philosophical Transactions,’ published in 1745, gave a very fair description of this animal from a living male specimen “brought,” as he tells us, “from Bengal, and shown in London.” There can be no doubt as to the identity of Parsons’s “Quadruped,” whatever we may say regarding the less accurate descriptions of Ray and Gesner, and it follows, consequently, that “_tragocamelus_” must be used as the earliest and most correct specific name of the Nilgai. In the supplement to his memoir on the genus _Antilope_ published in 1777, besides _A. tragocamelus_, Pallas introduced into his list an _Antilope picta_, founded upon Pennant’s “White-footed Antelope.” On referring to Pennant’s description and figure of this animal in his ‘Synopsis of Quadrupeds,’ there can be no doubt whatever that they likewise refer to the Nilgai. They were taken, as the author informs us, from a pair of animals living at Clermont in 1770. Following Pallas’s second name, a large number of authorities, as will be seen by our list of synonyms, have used _pictus_ and _picta_ as the specific name of the Nilgai; but, as we have already pointed out, _tragocamelus_ is prior in point of date, and being also unquestionably applicable, should have the preference. Erxleben’s name “_albipes_” and Zimmermann’s “_leucopus_,” both founded on Pennant’s “White-footed Antelope,” have likewise been proposed for the present species, but are also both later in date. Again, in 1827, Hamilton Smith adopted “_risia_” as the specific name of the Nilgai on account of some fancied objection to the term _picta_. But in this change few have been found to follow him. Finally, in 1836, Ogilby proposed to alter the name of the Nilgai to _hippelaphus_, because he thought it was the true Hippelaphus of Aristotle. This is possibly the case, but it does not necessitate the suggested change of the specific term.